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| I've seen houses with less structural stability than this. |
There are a number of different species of weaver birds, but in all of them the males construct incredibly elaborate hanging nests from blades of grass or palm leaves they find around them. The process takes a lot of time, and more importantly a lot of skill. Almost all the openings are at the bottom to dissuade predators from invading the nest. Females come and inspect the nests, and those males with the best construction and handiwork get a mate to help fill it once it's complete. In some species the females will even help the males complete the nests construction if the males have shown a solid enough base work and progress.
I want you to take a second to appreciate the amount of skill and practice required of these males to make these phenomenal nests. They have to tie knots, the kind we humans use daily, and from there they must hang and build upon a single blade of grass. Let me repeat this, it ties knots with only a beak and its feet. It takes years of practice for young males to really master a nest, and some never do. Then there is the absolutely heart breaking moment where a male realizes his nest simply isn't up to snuff, and has to simply CUT IT LOOSE and start again. Other species build huge communal nests which can last up to 100 years as every male in the colony will help construct and maintain it, as well as the little rooms within it. Because yes, they divide them into rooms for nesting, sleeping, and eating.
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| Social Weaver Bird nest. It's as large as it looks. |
Clearly, I am quite impressed with this amazing behavior. It's a little mind boggling how this complex, intricate skill would have evolved over time (though it seems to clearly be driven by nest predation as the goal is to create a safe nest for offspring).
So I will leave you with this video of David Attenburough narrating the process of a skilled male and a very novice male (who by the end you just want to hug...) create nests. Enjoy and be amazed.
Pictures:
http://www.telegraph.co.uk/earth/earthpicturegalleries/8655331/Animal-pictures-of-the-week-22-July-2011.html?image=33
http://journals.worldnomads.com/willlou/photo/1245/24442/Namibia/A-socialable-Weaver-Bird-nest#axzz32M8zPZdZ
My heart bleeds for that poor little guy! Sociable weavers of both sexes cooperate in building nests (Gavin Leighton has just published a paper on this in Journal of Ornithology), which is pretty cool. Funnily enough, I’ve also just published a paper with sociable weavers (although they are not the main focus). I imagine that the ability to build a nest is largely driven by genetics, while the precision of nest building is something that just has to be learnt. Is there any indication of this in the literature? Is there a gene x environment interaction for this behaviour? Go weaver birds!
ReplyDeleteI find it really interesting that there is a genetic disposition to form nests, but then there is one for language in humans so it shouldn't be so far out of the realm of possibility. I was unable to find any study directly testing for a link between genetics and environment for the nest behavior or shape (but if nobody has begun to work on it by the time I start grad school I call dibs!). I was able to find one study by Walsh et al in biology letters that looked at repeatability in nest morphology using the weaver birds as a test species, in which he seemed to believe that the actual form and shape of these unique nests is mostly due to leaned and observed behavior as opposed to a genetic drive to create such a complete sphere or add an exit tube.
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